content/child/worker_task_runner.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_CHILD_WORKER_TASK_RUNNER_H_
   6 #define CONTENT_CHILD_WORKER_TASK_RUNNER_H_
   7
   8 #include <map>
   9
  10 #include "base/callback_forward.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "base/synchronization/lock.h"
  13 #include "base/threading/platform_thread.h"
  14 #include "content/common/content_export.h"
  15 #include "content/public/child/worker_thread.h"
  16
  17 namespace base {
  18 class TaskRunner;
  19 }
  20
  21 namespace content {
  22
  23 class CONTENT_EXPORT WorkerTaskRunner {
  24  public:
  25   WorkerTaskRunner();
  26
  27   bool PostTask(int id, const base::Closure& task);
  28   int PostTaskToAllThreads(const base::Closure& task);
  29   static WorkerTaskRunner* Instance();
  30
  31   void DidStartWorkerRunLoop();
  32   void WillStopWorkerRunLoop();
  33
  34   base::TaskRunner* GetTaskRunnerFor(int worker_id);
  35
  36  private:
  37   friend class WorkerTaskRunnerTest;
  38
  39   using IDToTaskRunnerMap = std::map<base::PlatformThreadId, base::TaskRunner*>;
  40
  41   ~WorkerTaskRunner();
  42
  43   // It is possible for an IPC message to arrive for a worker thread that has
  44   // already gone away. In such cases, it is still necessary to provide a
  45   // task-runner for that particular thread, because otherwise the message will
  46   // end up being handled as per usual in the main-thread, causing incorrect
  47   // results. |task_runner_for_dead_worker_| is used to handle such messages,
  48   // which silently discards all the tasks it receives.
  49   scoped_refptr<base::TaskRunner> task_runner_for_dead_worker_;
  50
  51   IDToTaskRunnerMap task_runner_map_;
  52   base::Lock task_runner_map_lock_;
  53 };
  54
  55 }  // namespace content
  56
  57 #endif  // CONTENT_CHILD_WORKER_TASK_RUNNER_H_